This invention relates to a throwaway tip of a cutting tool having chip breaker groove for use in lathe turning.
As shown in FIG. 1, the throwaway tip 11 is generally of triangular shape and is fixedly secured to a shank 20 through a shaft 22 and a washer 21. The shank 20, the shaft 22 and the washer 21 are in combined form defining a holder 23 as shown in FIG. 1.
A conventional throwaway tip having chip breaker grooves is shown in FIG. 2. A groove 13 is uniformly formed along a cutting edge 12 of a tip 11. When the tip is driven toward the longitudinal direction, that is, toward the axial direction of a main shaft of a lathe to uniformly cut the outer diameter of the work-piece along its length, a chip is advanced along the transverse direction of the groove 13, so that the chip is cut at the groove edge portion 13a. On the other hand, when the tip is driven toward the transverse direction of the main shaft of the lathe for stepped portion machining or end surface machining of the work-piece, the chip is advanced in parallel with the groove, so that a continuous chip results which tends to clog around the cutting tool. It is troublesome to remove the clogged chip from the cutting tool, particularly in high speed machining.
Further, in the case of a conventional throwaway tip, since the cross sectional area of the groove is relatively large, the contacting area between the tip and the holder 23 is small. This results in difficulty insuring tight fix of the tip to the shank 20 of the holder 23. Furthermore, the cutting edge 12 and a particularly a land portion 24, the portion adjacent thereto, are apt to be damaged by chips.